1) Field of the Invention
The present invention relates to whipping creams which remain stable over a wide range of pH values; have a lowered fat content and also can be composed of milk fat solely to find direct application in the final uses; can be whipped as such to offer excellent flavor; show improved acid resistance sufficiently to permit formulation of souring agents to thereby produce stable whipped cream even after the resultant mix shows a pH value as low as pH 3.8; and possess improved freeze resistance in that they stay stable in terms of shape retention, water separation and the like after being frozen and thawed or unfrozen. Furthermore, the present invention is concerned with creams (hereinafter referred to as "pre-whipped cream") which, after once being whipped, can be filled in a whipping bag, frozen, then unfrozen and flowered for the second time. Furthermore, this invention relates to creams inclusive of pre-whipped creams having a lowered fat content and improved freeze resistance which are suited for use in the neutral pH range and in particular, to whipping creams which can be suitably used in the manufacture of aseptic products.
2) Background Art
Whipping creams have heretofore been used in various manners as a topping or filling material for confectionery and bakery products. However, such whipping creams, which in many instances show a pH value in the vicinity of neutrality and a fat content as high as not less than 40% by weight, are easy to be held in the stable emulsified state; they provide easily whipped creams with excellent whipping property and shape retention, whereas in turn, they suffer from the disadvantage or shortcoming that they presents invariably uniform, monotonous flavor.
In recent years, nevertheless, there is increasingly demanded a refreshing whipped cream (namely, an acid-resistant whipped cream) which has a low fat content and is formulated with a souring agent suck as various fruits, fruit juices and yogurts, as may be reflected by the increasingly diversified taste.
With a specific aim to improvement of productivity and working efficiency in making cakes, also, there exists a strong demand for a whipping cream which shows improved freeze resistance enough to permit freezing treatment after whipping, followed by unfreezing for direct use. On the other hand, there is greatly demanded a so-called pre-whipped cream which can be subjected to the sequential steps of whipping a cream composition; filling the whipped cream in a bag; keeping it under freeze; causing the same to become unfrozen; and squeezing the cream out of the bag to allow flowering. Some pre-whipped creams based on vegetable oils and fats have been put on the market, but such creams are inferior in flavor; consequently, there is an enormous demand for pre-whipped creams having an increased milk fat content or those having souring agents formulated therein.
Yet, addition of acid substances such as the ones described above not only brings about coagulation of proteins contained in a whipping cream, but also causes emulsification to be destroyed and the whipping function to deteriorate, resulting in water and oil separations and failure to achieve satisfactory overrun, and in the case of the whipping cream with a low fat content, such phenomenon has raised a particularly important problem.
As a substance acting to produce the preventive effect against coagulation of proteins in the acid pH range, there are used acid-resistant stabilizers such as pectin, carboxymethylcellulose and propylene glycol arginate, but such acid resistance stabilizers suffer from some defects; namely, they provide the resultant whipped cream with unsatisfactory emulsion stability and cause its overrun to deteriorate. In addition, such stabilizers, which impair the flavor of the resulting cream, can in no way be used in milk-fat based creams in which a particular emphasis is placed on the flavor, although they are usable unsatisfactorily in whipped cream based on vegetable oils and fats. Presently, any acid-resistant whipping cream based totally on milk fat has not yet been commercialized.
With reference to the emulsification system for acid-resistant whipping creams, there are proposed (1) a method of using a fatty acid ester of sorbitan, lecithin and a fatty acid ester of sucrose as an emulsifier (Japanese Unexamined Patent Publication No. 145,959/1978), (2) a method of utilizing a fatty acid ester of a polyglycerol and an organic acid ester of a monoglyceride in combination (Japanese Unexamined Patent Publication No. 111,639/1983), (3) a method of using a fatty acid ester of a polyglycerol and a stabilizer (naturally occurring polysaccharide or cellulose derivative) in combination (Japanese Unexamined Patent Publication No. 209,947/1983), (4) a method of utilizing in combination lecithin, a fatty acid ester of sucrose and not less than two kinds of fatty acid esters of a polyglycerol consisting of unsaturated and saturated fatty acids as a fatty acid constituent (Japanese Unexamined Patent Publication No. 54,635/1985), (5) a method of utilizing a fatty acid ester of a polyglycerol containing unsaturated and saturated fatty acids as a constituent fatty acid (Japanese Unexamined Patent Publication No. 112,747/1992), (6) a method of utilizing a fatty acid ester of a polyglycerol and chitosan in combination (Japanese Unexamined Patent Publication No. 144,660/1992), and the like. However, these methods are far from being fully satisfactory in that the resultant whipping cream undergoes solidification or coagulation during transport and the whipping cream can be whipped but only with inferior shape retention or characterized by a deteriorated flavor. The creams produced by these methods, when subjected to UHT treatment in order to produce a cream being preservable for a long period of time, come to require a prolonged length of time for foaming, and the resulting foamed cream encounters the problems such as inferior shape retention and increased tendency to give rise to water separation.
For the purpose of preventing coagulation of proteins in the acid pH range, there are proposed a treatment of proteins with protease (Japanese Unexamined Patent Publication No. 23,867/1989), use of whey protein hydrolyzed with an enzyme (Japanese Unexamined Patent Publication No. 257,838/1990), and utilization of an alkali metal salt of citric acid (Japanese Unexamined Patent Publication No. 51,054/1989), but these methods are not entirely satisfactory in terms of flavor.
A whipping cream requires the delicate, sophisticated technique and skill in achieving perfect foaming, and can only be cool-preserved hygienically for a storage period as short as 3 to 4 days. For the reason of this, a whipping cream is required that permits cakes with use of the resultant whipped cream to be produced in large quantities and then freeze-preserved, followed by unfreezing in required quantities for serving. However, such a whipping cream, on the occasion of freezing, undergoes emulsification destruction and protein denaturation accompanied by cryohydrate formation, and brings about quality deterioration such as cracking and shape loss. Consequently, freeze resistance to overcome such a problems is required of such whipping cream and is considered of particular importance in the case of a whipping cream with a lowered fat content.
On the other hand, the pre-whipped cream, which can allow the filling of a whipped cream in a bag, followed by storage under freeze and unfreezing for flowering on the occasion of necessity, is advantageous in that it is practically easy to be handled and can be flowered freely, and is highly demanded and required. In squeezing for flowering such whipped cream out of a bag after being unfrozen, nevertheless, there are faced the problems being different from the above-mentioned freeze resistance, such as coarse surface of the resultant whipped cream. Although some pre-whipped creams based on vegetable oils and fats have been made commercially available, they exhibit inferior flavor, and there is needed a pre-whipped cream with an increased content of milk fat enough to provide better flavor or a pre-whipped cream formulated with a souring agent, neither of which however has been commercialized yet.